Solved: “Unknown server tag telerik:RadScriptManager”

If you are using third-party .NET component libraries such as Telerik or DevExpress, you may come across the error message below while trying to include controls in your page.

Server Error in ‘/TestASPNET’ Application.

Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: Unknown server tag ‘telerik:RadScriptManager’.


Make sure to include 2 DLL files below in your project references of Visual Studio:

  • Telerik.Web.UI
  • Telerik.Web.UI.Skins

If you are still receiving the error above, add a reference to your Telerik assembly in your web.config file. You can use the following lines to make this reference.

  <pages viewStateEncryptionMode="Always" controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID">
      <add tagPrefix="telerik" namespace="Telerik.Web.UI" assembly="Telerik.Web.UI"/>

Solved: “Could not load file or assembly ‘Microsoft.SqlServer.Management.Sdk. The system cannot find the file specified”

You may run into the error below while doing development in Visual Studio:

Could not load file or assembly ‘Microsoft.SqlServer.Management.Sdk.Sfc, Version=, Culture=neutral, PublicKeyToken=89845dcd8080cc91′ or one of its dependencies. The system cannot find the file specified.


You are missing SQL Server libraries that connects Visual Studio to SQL Server database. In order to fix this issue, download and install these two packages from the following URL.

  • SharedManagementObjects.msi
  • DB2OLEDBV5_x64.msi


Note: The URL above is for SQL Server 2012. Download libraries for the version you use if it is not 2012 version.

How to install Entity Framework in Visual Studio?

There are 2 ways to install Microsoft’s data access technology, Entity Framework:

Use NuGet Package Manager UI:

  1. In Visual Studio, click “Tools > NuGet Package Manager > Manage NuGet Packages for Solution…”
  2. Search for “Entity”
  3. Select “EntityFramework” and click “Install”

Use NuGet Package Manager Console:

  1. In Visual Studio, click “Tools > NuGet Package Manager > Package Manager Console”
  2. Enter the following command:

    Install-Package EntityFramework

It will automatically install the latest version available (It’s 6.2.0 as of the date I wrote this post).

I used Visual Studio 2013 in the screenshots above.